Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Oct:44:431-443.
doi: 10.1016/j.meegid.2016.07.046. Epub 2016 Aug 2.

Hypothesis testing clarifies the systematics of the main Central American Chagas disease vector, Triatoma dimidiata (Latreille, 1811), across its geographic range

Patricia L Dorn  1 , Nicholas M de la Rúa  2 , Heather Axen  3 , Nicholas Smith  3 , Bethany R Richards  4 , Jirias Charabati  3 , Julianne Suarez  4 , Adrienne Woods  4 , Rafaela Pessoa  4 , Carlota Monroy  5 , C William Kilpatrick  3 , Lori Stevens  3
Affiliations

Hypothesis testing clarifies the systematics of the main Central American Chagas disease vector, Triatoma dimidiata (Latreille, 1811), across its geographic range

Patricia L Dorn et al. Infect Genet Evol. 2016 Oct.

Abstract

The widespread and diverse Triatoma dimidiata is the kissing bug species most important for Chagas disease transmission in Central America and a secondary vector in Mexico and northern South America. Its diversity may contribute to different Chagas disease prevalence in different localities and has led to conflicting systematic hypotheses describing various populations as subspecies or cryptic species. To resolve these conflicting hypotheses, we sequenced a nuclear (internal transcribed spacer 2, ITS-2) and mitochondrial gene (cytochrome b) from an extensive sampling of T. dimidiata across its geographic range. We evaluated the congruence of ITS-2 and cyt b phylogenies and tested the support for the previously proposed subspecies (inferred from ITS-2) by: (1) overlaying the ITS-2 subspecies assignments on a cyt b tree and, (2) assessing the statistical support for a cyt b topology constrained by the subspecies hypothesis. Unconstrained phylogenies inferred from ITS-2 and cyt b are congruent and reveal three clades including two putative cryptic species in addition to T. dimidiata sensu stricto. Neither the cyt b phylogeny nor hypothesis testing support the proposed subspecies inferred from ITS-2. Additionally, the two cryptic species are supported by phylogenies inferred from mitochondrially-encoded genes cytochrome c oxidase I and NADH dehydrogenase 4. In summary, our results reveal two cryptic species. Phylogenetic relationships indicate T. dimidiata sensu stricto is not subdivided into monophyletic clades consistent with subspecies. Based on increased support by hypothesis testing, we propose an updated systematic hypothesis for T. dimidiata based on extensive taxon sampling and analysis of both mitochondrial and nuclear genes.

Keywords: Central America; Chagas disease; Insect vector; Phylogeny; Systematics; Triatoma dimidiata.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Graphical representation of the subspecies (A) versus clinal variation (B) hypotheses. (A) Subspecies T. dimidiata maculipennis (yellow), T. dimidiata dimidiata (red), and T. dimidiata capitata (blue); support for this hypothesis is that the subspecies are monophyletic clades (as shown in cladeogram below map). (B) with T. dimidiata s.s. (red to blue) changing morphologically from north to south; the support for this hypothesis is that the proposed subspecies are not monophyletic (possible cladeogram below map).
Figure 2
Figure 2
Bayesian majority rule consensus ITS-2 phylogeny showing strong support for three monophyletic clades, T. dimidiata s.s., T. spp. aff. dimidiata, and T. spp. aff. dimidiata (cave). Note within T. dimidiata s.s. there are multiple non-monophyletic clades with strong support. Support for nodes is indicated by Bayesian posterior probability/ML % bootstrap support (>75% shown). Color codes indicate countries where each haplotype was found: Mexico = yellow, Belize = purple, Guatemala = green, Honduras = red, El Salvador = tan, Nicaragua = pink, Costa Rica = black, Panama= brown, Colombia = blue, Ecuador = orange; Prov = Providencia Island.
Figure 3
Figure 3
Median-joining ITS-2 haplotype network. The three well-supported clades are T. spp. aff. dimidiata (green), T. spp. aff. dimidiata (cave) (purple) and T. dimidiata s.s. (with the three previously proposed subspecies indicated by red: T. dimidiata dimidiata, yellow: T. dimidiata maculipennis, and blue T. dimidiata capitata). Mutation number (>2) between nodes is indicated, the outgroup is T. pallidipennis (black).
Figure 4
Figure 4
Bayesian majority rule consensus cyt b phylogeny showing strong support for three monphyletic clades: T. dimidiata s.s., T. spp. aff. dimidiata, and T. spp. aff. dimidiata (cave). Support for nodes is indicated by Bayesian posterior probability/ML % bootstrap support (>75%). The corresponding ITS-2 subspecies assignment are overlaid, indicated by colored boxes and lines (T. dimidiata maculipennis – yellow, T. dimidiata dimidiata – red, T. dimidiata capitata – blue, T. spp. aff. dimidiata – green). Haplotypes are color coded by country: Mexico = yellow, Belize = purple, Guatemala = green, Honduras = red, Nicaragua = pink, Costa Rica = black, Panama= brown, Colombia = blue, Ecuador = orange.
Figure 5
Figure 5
Median-joining cyt b haplotype network. Distinct taxa indicated by colors: T. dimidiata s.s. (red), T. spp. aff. dimidiata (green), and T. spp. aff. dimidiata (cave) (purple) and the outgroup, T. pallidipennis, (grey). Mutation number (>3) between nodes is indicated.
Figure 6
Figure 6
Bayesian majority rule consensus COI (A) and ND4 (B) phylogenies for T. dimidiata s.s., T. spp. aff. dimidiata, and T. spp. aff. dimidiata (cave). Taxa are collapsed into the monophyletic clades for simplicity. Support for nodes is indicated by Bayesian posterior probability/ML % bootstrap support (>75%).
Figure 7
Figure 7
Graphical representation of biogeography of T. dimidiata taxa: Geographic range of T. dimidiata s.s. (red), collection locations of T. spp. aff. dimidiata (green dots), and T. spp. aff. dimidiata (cave) (white dot).
See this image and copyright information in PMC

References

    1. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ. Basic local alignment search tool. Journal of molecular biology. 1990;215:403–410. - PubMed
    1. Bargues MD, Klisiowicz DR, Gonzalez-Candelas F, et al. Phylogeography and genetic variation of Triatoma dimidiata, the main Chagas disease vector in Central America, and its position within the genus Triatoma. PLoS neglected tropical diseases. 2008;2:e233. - PMC - PubMed
    1. Bargues MD, Zuriaga MA, Mas-Coma S. Nuclear rDNA pseudogenes in Chagas disease vectors: evolutionary implications of a new 5.8S+ITS-2 paralogous sequence marker in triatomines of North, Central and northern South America. Infect Genet Evol. 2014;21:134–156. - PubMed
    1. Blandon-Naranjo M, Zuriaga MA, Azofeifa G, Zeledon R, Bargues MD. Molecular evidence of intraspecific variability in different habitat-related populations of Triatoma dimidiata (Hemiptera: Reduviidae) from Costa Rica. Parasitol Res. 2010;106:895–905. - PubMed
    1. Brandelt HJ, Forster P, Röhl A. Median-joining networks for inferring intraspecific phylogenies. Mol Biol Evol. 1999;16:37–48. - PubMed

Publication types